A recent study from UX firm Bunnyfoot, published by eConsultancy, reveals that more than one-third of Internet users do not realize that Google Adwords are paid-for advertising units.

Back in 2012, Bunnyfoot carried out research and found that 41% of Google search users were unaware of the difference between organic and paid links.

Today, 36% of Internet users in Bunnyfoot's survey continue to be oblivious to the fact the ads labeled ads are ads. Furthermore, 27% said they did not know that Google had any form of advertising.That's despite a number of changes Google has made to better help users identify ads. Today, it even has the word 'ad' next to all paid adverts.

According to Jon Dodd, CEO and co-founder of Bunnyfoot, Google's changes have resulted in "little difference in real-world recognition of what is an ad" on Google's search results.

"If it is truly important that people can distinguish ads from non-ads (and presumably avoiding potentially misleading consumers is important) then the current Google design has not made significant change to this," wrote Dodd on Bunnyfoot's blog. "As our hundreds of user tests over the last decade have shown, it is very difficult to predict what customers' knowledge or understanding is. The clear value of user testing can be seen with the sort of results seen above."